Advaxis offers a tardy defense after FDA puts cancer vaccine on hold

Two weeks after reporting that its cancer vaccine spurred a positive response among a group of cervical cancer patients in a small clinical trial, Advaxis ($ADXS) waited until after the market closed today to reveal that the FDA has placed the same cancer vaccine--axalimogene filolisbac (ADXS-HPV)--on a clinical hold, slamming the brakes on four studies.

The hold, which the FDA told them about last Thursday, was prompted by the death of a patient. The company presented its side of the case, saying that the end-stage patient had been treated with the cancer vaccine in 2013 and was hospitalized in late July for the progression of cancer.

The patient tested positive for a "highly attenuated strain of Lm [Listeria monocytogenes] used in axalimogene filolisbac [its cancer vaccine uses Listeria--engineered to prevent an infection--to trigger an immune assault on cancer cells] which was incapable of causing infection and was highly sensitive to antibiotics," according to the company. "The patient received a course of intravenous antibiotics and was discharged."

A few weeks later she was dead.

According to Advaxis, which is likely going to get grilled about waiting 5 days to reveal the hold, company execs and the investigator involved concluded that the death was due to disease progression. The FDA, though, still evidently needs to have some questions answered before the trials resume.

That didn't sit well with investors, who immediately triggered a 36% drop in share price after the stock began trading again.

"The Agency has requested additional information to support a determination that axalimogene filolisbac did not contribute to the patient's death," the biotech said in a statement. "This additional information has now been provided to the FDA. Advaxis expects that this clinical hold will be resolved expeditiously and without significant interruption to our HPV clinical development program."

Two weeks ago Advaxis reported that its therapeutic vaccine was put through its paces among patients who had already failed at least one treatment. On average, says the Princeton, NJ-based biotech, these patients would have around 4 to 7 months to live, with no viable treatment options. But after 12 months of therapy in the single-arm study--where there was no comparator arm--the investigators tracked a 38.5% survival rate.